Vitrified bond super-abrasive wheel

Abstract

This vitrified bond super-abrasive wheel is provided with a super-abrasive grain layer containing diamond abrasive grains, a vitrified bond, and a filler. The filler is made of aluminum oxide. The vitrified bond contains, as a chemical composition, Si, Al, B, F, and an alkali metal. With respect to the total content of the chemical composition, the total content of Si and B is 50.0-80.0 mol%, the content of Al is 0.1-10.0 mol%, the content of F is 0.1-10.0 mol%, and the content of the alkali metal is 15.0-25.0 mol%.

Description

Vitrified Bond Superabrasive Wheel

[0001] The present disclosure relates to a vitrified bond superabrasive wheel. This application claims priority based on Japanese Patent Application No. 2025-002955, which is a Japanese patent application filed on January 8, 2025. All the descriptions contained in the Japanese patent application are incorporated herein by reference.

[0002] Conventionally, vitrified bond superabrasive wheels are described in, for example, Patent Documents 1 to 7.

[0003] Japanese Patent Application Laid-Open No. 2014-61585, Japanese Patent Application Laid-Open No. Hei 9-267264, Japanese Patent Application Laid-Open No. Hei 9-267266, Japanese Patent Application Laid-Open No. Sho 62-57873, Japanese Patent Application Laid-Open No. Sho 62-57874, Japanese Patent Application Laid-Open No. 2017-170554, Japanese Patent Application Laid-Open No. 2015-112685

[0004] The vitrified bond superabrasive wheel of the present disclosure is a vitrified bond superabrasive wheel provided with a superabrasive layer containing diamond abrasives, a vitrified bond, and a filler, wherein the filler is made of aluminum oxide. The vitrified bond contains Si, Al, B, F, and an alkali metal as its chemical composition, and with respect to the total content of the chemical composition, the total content of Si and B is 50.0 mol% or more and 80.0 mol% or less, the Al content is 0.1 mol% or more and 10.0 mol% or less, the F content is 0.1 mol% or more and 10.0 mol% or less, and the content of the alkali metal is 15.0 mol% or more and 25.0 mol% or less.

[0005] FIG. 1 is a photograph of a superabrasive layer 6 provided with an aggregate cutting edge structure surrounded by a line 7 composed of a vitrified bond 2, diamond abrasives 3, and a filler 4. FIG. 2 is a photograph of a superabrasive layer 6 not provided with an aggregate cutting edge structure. FIG. 3 is a schematic diagram of the superabrasive layer 6 provided with the aggregate cutting edge structure shown in FIG. 1. FIG. 4 is a side view of the superabrasive layer 6 provided with the aggregate cutting edge structure shown in FIG. 3. FIG. 5 is a schematic diagram of the superabrasive layer 6 not provided with the aggregate cutting edge structure shown in FIG. 2. FIG. 6 is a side view of the superabrasive layer 6 not provided with the aggregate cutting edge structure shown in FIG. 5.

[0006] [Problems to be Solved by the Invention] In the conventional vitrified bond superabrasive wheel, there was a problem of low grinding performance.

[0007] [Description of Embodiments of the Present Disclosure] First, the embodiments of the present disclosure will be listed and described.

[0008] When a vitrified bond superabrasive wheel is used for grinding a compound semiconductor, the strength of the superabrasive layer is insufficient. The reason is that the conventional vitrified bond superabrasive wheel does not have a configuration for withstanding high temperatures and high loads. Specifically, there is no combination of a filler with excellent high-temperature characteristics and a vitrified bond having a chemical composition with excellent affinity for the filler. Therefore, there was a problem of a large wear rate in the conventional vitrified bond superabrasive wheel.

[0009] The vitrified bond superabrasive wheel of the present disclosure is a vitrified bond superabrasive wheel provided with a superabrasive layer containing diamond abrasive grains, a vitrified bond, and a filler, wherein the filler is made of aluminum oxide. The vitrified bond contains Si, Al, B, F, and an alkali metal as its chemical composition, and with respect to the total content of the chemical composition, the total content of Si and B is 50.0 mol% or more and 80.0 mol% or less, the Al content is 0.1 mol% or more and 10.0 mol% or less, the F content is 0.1 mol% or more and 10.0 mol% or less, and the content of the alkali metal is 15.0 mol% or more and 25.0 mol% or less.

[0010] In a superabrasive wheel for grinding a compound semiconductor wafer such as SiC, it is necessary to withstand high temperatures and high loads. In the vitrified bond superabrasive wheel configured as described above, by containing stable aluminum oxide at high temperatures as a filler and containing aluminum, which is a filler constituent element, and fluorine, which has excellent chemical affinity with aluminum, in the vitrified bond, the grinding performance can be improved.

[0011] Preferably, the volume ratios of the diamond abrasive grains and the vitrified bond in the super abrasive grain layer are 10 to 40% by volume and 10 to 25% by volume, respectively, and the volume ratio of the filler to the vitrified bond is 2 to 5. Within this range, grinding performance such as grinding load and wear rate can be kept high.

[0012] Preferably, the average particle size of the diamond abrasive grains is 0.1 to 5.0 μm. Within this range, while increasing the strength of the super abrasive grain layer, the grinding load can be kept small.

[0013] Preferably, the average particle size of the filler is 0.1 to 5.0 μm. Within this range, while increasing the strength of the super abrasive grain layer, the grinding load can be kept small.

[0014] Preferably, the vitrified bond further contains an alkaline earth metal as the chemical composition, and the content of the alkaline earth metal relative to the total content of the chemical composition exceeds 0.0 mol% and is 2.9 mol% or less. Within this range, the glass softening temperature can be adjusted without excessively impairing the strength of the vitrified bond.

[0015] Preferably, the vitrified bond further contains a transition metal as the chemical composition, and the content of the transition metal relative to the total content of the chemical composition exceeds 0.0 mol% and is 0.8 mol% or less. Within this range, the strength can be adjusted without impairing the sinterability of the vitrified bond.

[0016] Preferably, the vitrified bond further contains an alkaline earth metal and a transition metal as the chemical composition, the content of the alkaline earth metal relative to the total content of the chemical composition exceeds 0.0 mol% and is 2.9 mol% or less, and the content of the transition metal relative to the total content of the chemical composition exceeds 0.0 mol% and is 0.8 mol% or less. Within this range, it is suitable for achieving both the strength and sinterability of the vitrified bond.

[0017] Preferably, the vitrified bond superabrasive wheel has an aggregate cutting edge structure including the diamond abrasive grains, the vitrified bond, and the filler on the working surface of the superabrasive layer after grinding, and the workpiece-facing surface thereof is flattened. As a result, when grinding a compound semiconductor wafer such as SiC, the cutting edge can withstand the high temperature and high load generated during grinding, enabling high-efficiency grinding.

[0018] Preferred embodiments of the present disclosure will be described below. The vitrified bond superabrasive layer of the present disclosure contains at least diamond abrasive grains, a vitrified bond, and a filler. The filler according to the present disclosure is characterized by being made of aluminum oxide. In other words, the filler according to the present disclosure substantially contains only aluminum oxide. The proportion of aluminum oxide in the filler is, for example, 98% by volume or more. The filler may contain silicon oxide or the like in addition to aluminum oxide. The composition of the filler can be determined by structural analysis using XRD and tissue analysis using SEM. The vitrified bond according to the present disclosure contains Si, Al, B, F, and an alkali metal as its chemical composition. With respect to the total content of the chemical composition, the total content of Si and B is 50.0 mol% or more and 80.0 mol% or less, the Al content is 0.1 mol% or more and 10.0 mol% or less, the F content is 0.1 mol% or more and 10.0 mol% or less, and the content of the alkali metal is 15.0 mol% or more and 25.0 mol% or less.

[0019] When the superabrasive wheel of the present disclosure having the above configuration is used for surface grinding of a compound semiconductor wafer such as SiC, it can exhibit excellent performance in terms of the balance between wear resistance and grinding load even under high temperature and high load conditions generated during grinding. In surface grinding of compound semiconductor wafers, the cutting edge temperature and load are higher compared to silicon semiconductors, and there has been a problem that the wear resistance and grinding resistance deteriorate in conventional superabrasive layers. In the present disclosure, alumina (aluminum oxide), which has excellent high-temperature characteristics, is used as a filler, and a vitrified bond composition having excellent chemical affinity with alumina is used, so the resistance to temperature and load is significantly improved.

[0020] In the present disclosure, the volume ratios of diamond abrasive grains and vitrified bonds in the entire superabrasive grain layer excluding pores are 10.0 to 40.0% by volume and 10.0 to 25.0% by volume, respectively, and it is preferable that the volume ratio of the filler to the vitrified bond is 2.0 to 5.0. Thereby, a superabrasive grain layer excellent in grinding performance can be obtained. In a normal vitrified bond superabrasive grain wheel, natural pores remaining during sintering and artificial pores formed from the skeletons of pore-forming materials are formed. Although pores can be included in the superabrasive grain layer of the present disclosure, in the present disclosure, the volume of pores is not counted as the structure of the superabrasive grain layer. As a more suitable composition ratio of the superabrasive grain layer, the volume ratio of the abrasive grains is 12.0 to 40.0% by volume. Or the volume ratio of the abrasive grains is 17.1 to 38.1% by volume. Or the volume ratio of the abrasive grains is 18.2 to 33.2% by volume. The volume ratio of the vitrified bond is preferably 12.0 to 20.0% by volume. Or the volume ratio of the vitrified bond is preferably 15.0 to 18.0% by volume. The volume ratio of the filler to the vitrified bond (volume of filler / volume of vitrified bond) is preferably 2.5 to 4.5. The volume ratio of the filler to the vitrified bond (volume of filler / volume of vitrified bond) is preferably 2.9 to 3.9. Note that among the volume ratios in the entire superabrasive grain layer excluding pores, the remaining part obtained by subtracting the volume ratio of diamond abrasive grains and the volume ratio of vitrified bonds is the volume ratio of the filler.

[0021] The present disclosure is particularly suitable for application to a vitrified bond superabrasive grain wheel having diamond abrasive grains with an average particle size of 0.1 to 5.0 μm. In a relatively fine-grained vitrified bond superabrasive grain wheel, the strength of the superabrasive grain layer tends to decrease. As a result, deterioration of grinding performance due to high temperature and high load during grinding of a compound semiconductor wafer becomes a problem, and thus the effects of the present disclosure are remarkably exhibited. The average particle size of the diamond abrasive grains is preferably 1.2 μm or more and 5.0 μm or less. The average particle size of the diamond abrasive grains is preferably 0.10 μm or more and 1.2 μm or less. The average particle size of the diamond abrasive grains is preferably 0.10 μm or more and 0.80 μm or less.

[0022] Also, the filler according to the present disclosure preferably has an average particle size of 0.1 to 5.0 μm. When the average particle size of the filler is 0.1 μm or more, the strength of the super abrasive grain layer increases and the wear resistance improves. Also, when it is 5.0 μm or less, the super abrasive grain layer is appropriately broken, so that the grinding resistance can be reduced. The average particle size of the filler is preferably 1.2 μm or more and 5.0 μm or less. The average particle size of the filler is preferably 0.10 μm or more and 1.2 μm or less. The average particle size of the diamond abrasive grains is preferably 0.10 μm or more and 0.60 μm or less.

[0023] Si and B are elements that form the skeleton of the glass. If there is too much, the sinterability of the super abrasive grain layer decreases and the strength of the super abrasive grain layer deteriorates. On the other hand, if there is too little, the glass strength decreases and the strength of the super abrasive grain layer deteriorates. The alkali metal element is an element that adjusts the softening point and strength of the glass. If there is too much, the glass strength and softening point decrease and the resistance to grinding temperature and load deteriorates. On the other hand, if there is too little, the sinterability of the super abrasive grain layer decreases and the strength of the super abrasive grain layer deteriorates. Al is an element that is a glass skeleton element and at the same time contributes to the affinity with the filler (alumina). If there is too much, it reacts with F described later and deteriorates the affinity between the glass and the filler. On the other hand, if there is too little, the affinity with the filler is insufficient. F is an element that greatly contributes to the affinity with the filler. If there is too much, the glass strength and softening point decrease and the resistance to grinding temperature and load deteriorates. On the other hand, if there is too little, the affinity with the filler is insufficient.

[0024] In addition, as a more suitable chemical composition range of the vitrified bond according to the present disclosure, the total content of Si and B is preferably 55.0 to 75.0 mol%, the Al content is 1.0 to 8.0 mol%, the F content is 1.0 to 8.0 mol%, and the content of the alkali metal is 17.5 to 22.5 mol%. Within this range, the grinding performance of the vitrified super abrasive grain wheel can be maximized.

[0025] The total content of Si and B is preferably 56.9 mol% or more and 69.0 mol% or less. The total content of Si and B is preferably 70.5 mol% or more and 75.2 mol% or less. The total content of Si and B is preferably 57.5 mol% or more and 69.0 mol% or less.

[0026] It is preferable that the Al content is 1.6 mol% or more and 7.5 mol% or less. It is more preferable that the Al content is 3.7 mol% or more and 6.7 mol% or less.

[0027] It is preferable that the Fl content is 1.3 mol% or more and 7.1 mol% or less. It is more preferable that the F content is 1.7 mol% or more and 5.5 mol% or less.

[0028] It is preferable that the content of the alkali metal is 18.3 mol% or more and 22.3 mol% or less. It is more preferable that the content of the alkali metal is 18.9 mol% or more and 22.0 mol% or less.

[0029] The vitrified bond further contains an alkaline earth metal as the chemical composition, and it is preferable that the content of the alkaline earth metal exceeds 0.0 mol% and is 2.9 mol% or less with respect to the total content of the chemical composition. It is more preferable that the content of the alkaline earth metal is 0.3 mol% or more and 2.9 mol% or less. It is even more preferable that the content of the alkaline earth metal is 0.4 mol% or more and 2.8 mol% or less.

[0030] The vitrified bond further contains a transition metal as the chemical composition, and it is preferable that the content of the transition metal exceeds 0.0 mol% and is 0.8 mol% or less with respect to the total content of the chemical composition. It is more preferable that the content of the transition metal is 0.1 mol% or more and 0.8 mol% or less. It is even more preferable that the content of the transition metal is 0.3 mol% or more and 0.7 mol% or less.

[0031] The vitrified bond further contains an alkaline earth metal and a transition metal as the chemical composition, and the content of the alkaline earth metal with respect to the total content of the chemical composition is more than 0.0 mol% and 2.9 mol% or less, and the content of the transition metal with respect to the total content of the chemical composition is more than 0.0 mol% and 0.8 mol% or less, which is even better. It is even better that the content of the alkaline earth metal with respect to the total content of the chemical composition is 0.3 mol% or more and 2.9 mol% or less, and the content of the transition metal with respect to the total content of the chemical composition is 0.1 mol% or more and 0.8 mol% or less. It is even better that the content of the alkaline earth metal with respect to the total content of the chemical composition is 0.4 mol% or more and 2.8 mol% or less, and the content of the transition metal with respect to the total content of the chemical composition is 0.3 mol% or more and 0.7 mol% or less. The vitrified bond preferably contains Si, B, Al, F, an alkali metal, optionally an alkaline earth metal, and optionally a transition metal as the chemical composition, and the balance consists of inevitable impurities.

[0032] Next, another aspect of the present disclosure will be described. Another aspect of the present disclosure is a superabrasive wheel including diamond abrasive grains, a vitrified bond, and a filler, and having an aggregate cutting edge structure including diamond abrasive grains, a vitrified bond, and a filler on the working surface after grinding a workpiece (particularly a compound semiconductor wafer), and the surface facing the workpiece is flattened.

[0033] In the superabrasive layer having an aggregate cutting edge structure, it is possible to suppress premature chipping of the cutting edge in the surface grinding of a compound semiconductor wafer where high temperature and high load are problems. In a conventional superabrasive layer, the strength of the vitrified bond supporting the cutting edge (abrasive grains) is insufficient, so the wear resistance deteriorates. In the present disclosure, the vitrified bond strengthened by the filler can hold the diamond abrasive grains for a long time, so the wear resistance is improved. The central portion of the aggregate cutting edge structure is rubbed by the workpiece (semiconductor wafer) and worn and flattened.

[0034] Fig. 1 is a photograph of a superabrasive layer 6 provided with an aggregate cutting edge structure surrounded by a line 7 composed of a vitrified bond 2, diamond abrasive grains 3, and a filler 4. Fig. 2 is a photograph of a superabrasive layer 6 without an aggregate cutting edge structure. Fig. 3 is a schematic diagram of the superabrasive layer 6 provided with the aggregate cutting edge structure shown in Fig. 1. Fig. 4 is a side view of the superabrasive layer 6 provided with the aggregate cutting edge structure shown in Fig. 3. Fig. 5 is a schematic diagram of the superabrasive layer 6 without an aggregate cutting edge structure shown in Fig. 2. Fig. 6 is a side view of the superabrasive layer 6 without an aggregate cutting edge structure shown in Fig. 5.

[0035] As shown in Figs. 1, 3, and 4, when an aggregate cutting edge structure (a region surrounded by a line 7) composed of a vitrified bond 2, diamond abrasive grains 3, and a filler 4 is provided, it becomes possible to suppress the detachment of the diamond abrasive grains 3 constituting the cutting edge. In the aggregate cutting edge structure, a plurality of diamond abrasive grains 3 form a plane with respect to the direction facing the wafer (workpiece) indicated by an arrow 11. As a result, it is possible to prevent only one diamond abrasive grain 3 from protruding, and as a result, the detachment of the diamond abrasive grains 3 can be suppressed. On the other hand, as shown in Figs. 2, 5, and 6, when no aggregate cutting edge structure is provided, one diamond abrasive grain 3 constitutes the cutting edge 17. As a result, the diamond abrasive grains 3 are likely to detach.

[0036] The above two types of superabrasive layers can be manufactured by the manufacturing process of a normal vitrified bond superabrasive layer. Prepare diamond abrasive grains, alumina filler, and glass frit of a desired particle size. Glass frit is powder glass obtained by pulverizing glass to an appropriate size. The chemical composition of the glass frit may be the composition according to the vitrified bond of the present disclosure. These starting materials can be manufactured by means known to those skilled in the art, for example, by a process of wet mixing, cold forming, firing in the atmosphere, base bonding, and shaping.

[0037] Whether aluminum and fluorine are contained in the vitrified bond in the superabrasive layer can be easily identified by observation means such as SEM / EDS and TEM / EDS. When analyzing a more detailed glass composition, it will be described later.

[0038] The volume ratios of diamond abrasive grains, fillers, and vitrified bonds in the super abrasive grain layer can be analyzed from electron micrographs such as SEM. As an example, select a field of view and magnification in which 50 or more diamond abrasive grains and fillers are each included, and use image analysis software such as WinRoof to determine the area ratios of diamond abrasive grains, fillers, and vitrified bonds. The area ratios of diamond abrasive grains, fillers, and vitrified bonds can be taken as volume ratios. Although it is obvious to those skilled in the art, in a super abrasive grain layer using a general vitrified bond, the abrasive grains, fillers, and vitrified bonds can be distinguished from the color tone of the tissue photograph. In the example of FIG. 1, black particles can be recognized as diamond abrasive grains, white particles as fillers, and an intermediate-colored amorphous substance as a vitrified bond.

[0039] The average particle size of diamond abrasive grains and the average particle size of fillers in the super abrasive grain layer can also be analyzed from electron micrographs such as SEM. Using the same procedure as the above-mentioned volume ratio, measure the Feret diameter of 50 or more particles using image analysis software, and take the Median diameter as the average particle size.

[0040] When identifying the detailed composition of the vitrified bond, the following procedure is recommended. First, determine the volume ratios of the fillers and vitrified bonds to the super abrasive grain layer using the above-mentioned method in advance. Next, collect a predetermined amount of tissue pieces of the super abrasive grain layer and crush them with a crushing device. The crushed powder of the super abrasive grain layer is calcined in air to burn off only the diamond abrasive grains contained in the super abrasive grain layer, and a residue powder composed only of the vitrified bond and the filler is obtained. Measure the true specific gravity of the entire residue powder using a pycnometer, and determine the specific gravity of the vitrified bond by using the previously determined volume ratio of filler:vitrified bond and the known specific gravity of alumina. From these numerical values, the weight ratio of filler:vitrified bond can be determined.

[0041] After that, the chemical composition in the residue powder is identified by ICP and combustion ion chromatography. More specifically, Si, Al, B, alkali metals, alkaline earth metals, and transition metal elements are analyzed by ICP. Si and F are analyzed by combustion ion chromatography. From these analysis results, the ratio "Si<ICP> / Si<IC>" of the Si analysis amount "Si<ICP>" by ICP to the Si analysis amount "Si<IC>" by combustion ion chromatography is determined. This ratio is multiplied by the F analysis amount "F<IC>" by combustion ion chromatography to obtain the equivalent ICP analysis amount "F<ICP>" of F. On the other hand, regarding the Al analysis amount by ICP, the amount of Al contained in the filler is subtracted from the previously determined weight ratio of the filler: vitrified bond. For example, if the weight ratio of the filler: vitrified bond is 1:1 and the Al analysis amount by ICP is 10 parts by weight, it is assumed that the amount of Al contained in the vitrified bond is 5 parts by weight.

[0042] The chemical composition (weight ratio) of the vitrified bond is determined from the weight ratios of all elements determined by the above procedure, and the chemical composition (molar ratio) of the vitrified bond can be identified by using the atomic weights of each element. Thereby, the ratio of the number of moles of each component contained in the vitrified bond to the total number of moles of the entire vitrified bond can be calculated.

[0043] [Details of Embodiments of the Present Disclosure] (Example 1)

[0044]

[0045] First, diamond abrasive grains and fillers having the average particle sizes shown in Table 1 were prepared. As the fillers, alumina, silicon carbide, graphite, and h-BN were used. Also, resin beads with an average diameter of 1.0 to 5.0 μm were prepared as the pore-forming material. Further, a glass frit having a softening temperature of 850°C was prepared as the glass frit constituting the vitrified bond. Composition 1 of the vitrified bond for Sample No. 1 contains Al and F, Composition 2 for Sample No. 201 does not contain Al, and Composition 3 for Sample No. 202 does not contain F.

[0046] Using a ball mill and a bead mill, the glass frit was processed into fine powder in a pre-grinding step so that the average particle size was comparable to each diamond particle size.

[0047] These raw material powders and wax as a molding aid were put into a pot and mixed for 72 h using a wet ball mill with zirconia balls.

[0048] After mixing the diamond abrasive grains, glass frit powder, and filler, the slurry composed of these mixtures was recovered, and a dried body was obtained by evaporation drying, and this was sized and sieved using a sieve with a predetermined mesh size to obtain granulated bodies.

[0049] This granulated body was filled into a mold and warm compression molding was performed at a temperature of 150 °C and a surface pressure of 0.2 ton (0.2 × 1000 × 9.8 N) / cm ２ to obtain a compacted powder body.

[0050] The compacted powder body was charged into an air furnace, held at a maximum temperature of 650 to 950 °C for 2 h, and then furnace-cooled to obtain a sintered body.

[0051] The sintered body was attached to an aluminum alloy base with a wheel diameter of 200 mm, and the inner and outer circumferences and the surface were processed using a WA grinding wheel with a particle size of #240 to produce vitrified bond superabrasive wheels having diamond abrasive grains and fillers with sample numbers 1, 201 to 205 shown in Table 1. It was confirmed that the composition of the vitrified bond was the same as the composition of the glass frit which is the raw material of the vitrified bond.

[0052] These superabrasive wheels in Table 1 were subjected to grinding under the following conditions. The apparatus was HRG300 manufactured by Tokyo Seimitsu, and the work material was a generally available 6-inch single crystal SiC wafer (dummy grade 4H-N). The processing conditions were a spindle rotation speed of 1750 rpm, a table rotation speed of 300 rpm, a wheel feed rate of 0.6 μm / s, and a processing thickness of 25 μm.

[0053] In the evaluation, the wear rate (change amount of the height of the superabrasive layer 6 before and after wear / change amount of the thickness of the work (wafer) of the ground part before and after grinding), load current, and grinding resistance were measured on both the Si surface and the C surface of the SiC wafer, and the average value was obtained.

[0054] Regarding the processing results, it was found that in Sample No. 1 where alumina is a filler and the vitrified bond contains Al and F, a small wear rate is shown.

[0055] The load current and the grinding resistance are generally related. The load current tended to be large in samples with a large grinding resistance. In Sample No. 204 with silicon carbide as a filler, it is considered that the friction with the silicon carbide constituting the work increased, and the grinding resistance and the load current became larger compared to Sample No. 1.

[0056] (Example 2)

[0057]

[0058]

[0059] Superabrasive grain layers of Sample Nos. 11 to 28 and 111 to 120 having diamond abrasive grains, vitrified bonds, and fillers as shown in Tables 2 and 3 were produced in the same manner as in Example 1. The ratios of diamond abrasive grains, vitrified bonds, and fillers were adjusted by changing the ratios of the raw materials to be mixed. All the fillers were alumina. Also, as the glass frit constituting the vitrified bond, a glass frit with a softening temperature of 850°C was prepared. The glass frit contains Si, Al, B, F, alkali metals, and alkaline earth metals as its chemical composition. With respect to the total content of the chemical composition, the total content of Si and B is 50.0 to 80.0 mol%, the Al content is 0.1 to 10.0 mol%, the F content is 0.1 to 10.0 mol%, the content of alkali metals is 15.0 to 25.0 mol%, and the content of alkaline earth metals exceeds 0.0 mol% and is 2.9 mol% or less.

[0060] Superabrasive grain layers having vitrified bonds with the compositions shown in Tables 2 and 3 were attached to the same base alloy as in Example 1 to obtain vitrified bond superabrasive wheels.

[0061] It was subjected to grinding under the same conditions as in Example 1. The grinding results are shown in Tables 2 and 3. In sample numbers 11 to 28, the volume ratios of diamond abrasive grains and the vitrified bond in the super abrasive grain layer are respectively 10.0% by volume or more and 40.0% by volume or less, 10.0% by volume or more and 25.0% by volume or less, and the volume ratio of the filler to the vitrified bond is 2 to 5. It was found that in the vitrified bond super abrasive grain wheel configured as described above, more favorable results were obtained in terms of the wear rate.

[0062] (Example 3)

[0063]

[0064]

[0065] Super abrasive grain layers of sample numbers 31 to 40 and 131 to 140 having diamond abrasive grains, a vitrified bond, and a filler as required as shown in Tables 4 and 5 were produced in the same manner as in Example 1.

[0066] Sample numbers 31 to 40 in Tables 4 and 5 have the same composition of filler and vitrified bond as sample number 1. In sample numbers 31 to 40, the average particle sizes of the diamond abrasive grains are different from each other.

[0067] Sample numbers 231 to 240 are obtained by removing the filler from sample numbers 31 to 40. Also, sample numbers 231 to 240 are obtained by removing Al and F in the vitrified bond from sample numbers 31 to 40.

[0068] Using these materials of sample numbers 31 to 40 and 231 to 240, a super abrasive grain layer was produced in the same manner as in Example 1. A super abrasive grain layer having a vitrified bond with the composition shown in Tables 4 and 5 was attached to the same base metal as in Example 1 to obtain a vitrified bond super abrasive grain wheel.

[0069] It was subjected to grinding under the same conditions as in Example 1. The grinding results are shown in Tables 4 and 5.

[0070] In sample numbers 231 to 240, compared with sample numbers 31 to 40, since the vitrified bond does not contain an alumina filler and does not contain Al and F in the vitrified bond, it was found that the wear rate deteriorated. Also, sample numbers 33 to 40 with an average diamond grit particle size of 0.1 μm or more and 5.0 μm or less had good results in terms of wear rate, load current, and grinding resistance compared to sample numbers 31 and 32. In sample numbers 31 and 32, although the wear rate decreased because the average diamond grit particle size was larger compared to sample numbers from 33 to 40, the load current and grinding resistance were inferior to those of sample numbers 33 and 40. It can be said that the average diamond grit particle size was optimized in sample numbers 33 to 40.

[0071] (Example 4)

[0072]

[0073] Superabrasive grain layers of sample numbers 41 to 47 and 141 to 144 having diamond abrasive grains, a vitrified bond, and optionally a filler as shown in Table 6 were produced in the same manner as in Example 1.

[0074] Sample numbers 41 to 47 and 141 to 144 in Table 6 have a filler and a vitrified bond of the same composition as sample number 1. In sample numbers 41 to 47 and 141 to 144, the average particle size of the filler is different from each other.

[0075] Using the materials of these sample numbers 41 to 47 and 141 to 144, a superabrasive grain layer was produced in the same manner as in Example 1. A superabrasive grain layer having a vitrified bond with the composition shown in Table 6 was attached to the same base metal as in Example 1 to obtain a vitrified bond superabrasive grain wheel.

[0076] This was subjected to grinding under the same conditions as in Example 1. The grinding results are shown in Table 6. It was found from Table 6 that when the average particle size of the filler is 0.1 μm to 5.0 μm or less, balanced results can be obtained in terms of wear rate, load current, and grinding resistance.

[0077] (Example 5)

[0078]

[0079]

[0080] Diamond abrasive grains, alumina filler, and a vitrified bond having the compositions shown in Tables 7 and 8 were prepared. The "-" in Tables 7 and 8 indicates that the composition is 0.0 mol%.

[0081] Superabrasive grain layers of sample numbers 51 to 73 and 251 to 257 having diamond abrasive grains, a filler, and a vitrified bond as shown in Tables 7 and 8 were produced in the same manner as in Example 1.

[0082] Superabrasive grain layers having the compositions shown in Tables 7 and 8 were attached to the same base metal as in Example 1 to obtain vitrified bond superabrasive wheels.

[0083] This was subjected to grinding under the same conditions as sample number 1. The grinding results are shown in Tables 9 and 10.

[0084]

[0085]

[0086] Compared with sample numbers 51 to 70 in which the total content of Si and B is 50.0 mol% or more and 80.0 mol% or less, the content of Al is 0.1 mol% or more and 10.0 mol% or less, the content of F is 0.1 mol% or more and 10.0 mol% or less, and the content of alkali metal is 15.0 mol% or more and 25.0 mol% or less with respect to the total content of the vitrified bond chemical composition, the composition of the vitrified bond is out of this range in sample numbers 71 to 73 and 251 to 257. Therefore, it was found that the wear rate deteriorated.

[0087] It should be considered that all aspects of the embodiments and examples disclosed this time are illustrative and not restrictive. The scope of the present invention is shown not by the above-described embodiments but by the claims, and it is intended that all meanings equivalent to the claims and all changes within the scope are included.

[0088] 2 Vitrified bond, 3 Diamond abrasive grains, 4 Filler, 6 Superabrasive layer, 7 Line, 11 Arrow, 17 Cutting edge.

Claims

1. A vitrified bond superabrasive wheel comprising a superabrasive layer containing diamond abrasive grains, a vitrified bond, and a filler, wherein the filler is made of aluminum oxide, and the vitrified bond contains Si, Al, B, F, and alkali metals as a chemical composition, and the total content of Si and B is 50.0 mol% or more and 80.0 mol% or less, the Al content is 0.1 mol% or more and 10.0 mol% or less, the F content is 0.1 mol% or more and 10.0 mol% or less, and the alkali metal content is 15.0 mol% or more and 25.0 mol% or less of the total content of the chemical composition.

2. The vitrified bond superabrasive wheel according to claim 1, wherein the volume ratio of the diamond abrasive grains to the superabrasive layer is 10.0% by volume or more and 40.0% by volume or less, the volume ratio of the vitrified bond to the superabrasive layer is 10.0% by volume or more and 25.0% by volume or less, and the volume ratio of the filler to the vitrified bond is 2.0 to 5.

0.

3. The vitrified bond superabrasive wheel according to claim 1 or claim 2, wherein the average particle size of the diamond abrasive grains is 0.1 μm or more and 5.0 μm or less.

4. The vitrified bond superabrasive wheel according to any one of claims 1 to 3, wherein the average particle size of the filler is 0.1 μm to 5.0 μm or less.

5. The vitrified bond superabrasive wheel according to any one of claims 1 to 4, wherein the vitrified bond further contains an alkaline earth metal as part of the chemical composition, and the content of the alkaline earth metal relative to the total content of the chemical composition is greater than 0.0 mol% and less than or equal to 2.9 mol%.

6. The vitrified bond superabrasive wheel according to any one of claims 1 to 5, wherein the vitrified bond further contains a transition metal as part of its chemical composition, and the content of the transition metal relative to the total content of the chemical composition is greater than 0.0 mol% and less than or equal to 0.8 mol%.

7. The vitrified bond superabrasive wheel according to any one of claims 1 to 6, wherein the vitrified bond further comprises an alkaline earth metal and a transition metal as part of the chemical composition, the content of the alkaline earth metal relative to the total content of the chemical composition is greater than 0.0 mol% and less than or equal to 2.9 mol%, and the content of the transition metal relative to the total content of the chemical composition is greater than 0.0 mol% and less than or equal to 0.8 mol%.

8. A vitrified bond superabrasive wheel comprising a superabrasive layer containing diamond abrasive grains, a vitrified bond, and a filler, wherein the working surface of the superabrasive layer after grinding has a aggregate cutting edge structure in which the diamond abrasive grains, the vitrified bond, and the filler are included and the workpiece-facing surface is flattened.

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